This is a nice collection of routes:
http://www.sportsfun.com/gaba/ridemaps.html
Ride with this club on a weekend too.
Also if you want a climb, don't miss riding up South Mountain ('To the Towers') from the Central Ave entrance. Riding around South Mountain ('Around The Mountain') gets you out of the city for the south and western part of it which is nice. (both routes are in the link above) Do both aroudn and up which is always fun.
Al